trans seal replace
Fleet Mechanic
Joined: Sep 2003
Posts: 1,716
Likes: 15
A leaking extension housing seal on a 2WD trans could be just a worn-out seal. But it could also be a seal that just couldn't seal anymore because of too much yoke movement caused by a worn extension housing bushing.
The driveshaft yoke slips over the splines on the transmission's output shaft. The smooth outer diameter of the yoke rides inside the extension housing's output bushing. The seal presses into a recessed area just behind the bushing. If the bushing is too worn, the yoke moves around too much, and rounds-out the seal, causing it to leak. If that is the case, a new seal will "cure" it for a while, until it gets rounded-out too, and it leaks again.
You can test for bushing wear by blocking the rear wheels, parking brake ON, trans in Neutral. Grab the yoke real close to the trans, and try to move it up-down. Use some muscle. Don't just grab further back, as you will get some tilting play that way, need to grab it right up by the trans. A little bit is OK, a lotta bit is bad. I can't quantify that into fractions of an inch of movement, as I move when the yoke moves, and I lose reference. Doing it from experience.
If the bushing needs to be replaced, it can be done with just the driveshaft out, but it requires special tools just for that purpose to pull and press in the new bushing. I don't have those tools, so when needed I have taken the extension housings off and worked on removing/installing the bushing off of the vehicle. Which also makes seal pulling and installing a simple job. But doing this is not a total beginner's job (note: it is sometimes difficult to assess one's experience over the internet
)
The driveshaft yoke slips over the splines on the transmission's output shaft. The smooth outer diameter of the yoke rides inside the extension housing's output bushing. The seal presses into a recessed area just behind the bushing. If the bushing is too worn, the yoke moves around too much, and rounds-out the seal, causing it to leak. If that is the case, a new seal will "cure" it for a while, until it gets rounded-out too, and it leaks again.
You can test for bushing wear by blocking the rear wheels, parking brake ON, trans in Neutral. Grab the yoke real close to the trans, and try to move it up-down. Use some muscle. Don't just grab further back, as you will get some tilting play that way, need to grab it right up by the trans. A little bit is OK, a lotta bit is bad. I can't quantify that into fractions of an inch of movement, as I move when the yoke moves, and I lose reference. Doing it from experience.
If the bushing needs to be replaced, it can be done with just the driveshaft out, but it requires special tools just for that purpose to pull and press in the new bushing. I don't have those tools, so when needed I have taken the extension housings off and worked on removing/installing the bushing off of the vehicle. Which also makes seal pulling and installing a simple job. But doing this is not a total beginner's job (note: it is sometimes difficult to assess one's experience over the internet
)
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